Doing a little research and found this info:
You can apply a coat of clear to seal the masking, any bleed under will be clear and shouldn't affect the base coat or the separation. Applying a coat of the base color over the masking will do something similar, the difference being the bleed under will be the color of the base. This can be especially useful if the finished model doesn't have a clear coat, it "just looks right" not having any clear along the separation line if you aren't going to clearcoat the rest of the car. However, it can be a problem if applying another coat of the base color would make it darker or otherwise shift the color. On certain metallic or candy paints, another coat of the base color would show up nearly as much as the second color bleeding under the masking.